Molding device provided with a controlled means for clampingly attaching a half-mold by means of slidable attachment bolts

ABSTRACT

Disclosed is a molding device for a machine for manufacturing containers, including: two half-molds; two mold carriers, each of which is provided with a recess for receiving a corresponding half-mold; and at least one retractable attachment bolt that is slidably mounted in at least one mold carrier between an operative position, in which the bolt is extended to removably attach the corresponding half-mold in a clampingly mounted position against the back wall of the corresponding recess, and a retracted position, in which the bolt releases the half-mold, characterized in that each bolt and/or the corresponding half-mold include a clamping strip that is angled so as to cause the half-mold to bear against the back wall of the recess during the sliding of the attachment bolt from the retracted position thereof to the operative position thereof.

The present invention concerns a molding device for a machine forproducing containers, notably bottles.

The present invention more particularly concerns a molding device for amachine for producing containers, notably bottles, in thermoplasticmaterial by blowing or drawing-blowing a preform, the molding deviceincluding:

-   -   two half-molds each of which is provided with a half-imprint and        each of which includes a front joint face and a rear face;    -   two mold-carriers each of which is provided with a recess        intended to receive an associated half-mold in a mounted        position in which the rear face of the half-mold is in contact        with the bottom of the recess; and    -   at least one retractable fixing bolt that is slidably mounted in        at least one mold-carrier to slide between an active position in        which it is extended to fix in demountable manner the associated        half-mold in the mounted position clamped against the bottom of        the associated recess by at least one locking face of each        fixing bolt bearing against an associated fixing face of the        half-mold, and a retracted position in which it releases the        half-mold.

There are known in the prior art molding devices intended to equipmachines for producing containers, notably but not exclusively so-called“rotary machines” including a carousel provided circumferentially with aparticular number of identical blowing stations.

Plastic material containers, such as bottles, flasks, etc. are producedtherein from preforms or blanks pre-heated in a heat treatment oven.Depending on the number of imprints in the molds, one or more preformsare fed in this way to a station of the machine to be inserted into amolding device with which blowing or drawing-blowing means areassociated.

Such molding devices include at least one mold constituted of twohalf-molds supported by respective mold-carriers that are mounted to bemobile relative to each other.

Each half-mold is generally fixed to an associated mold-carrier in aremovable manner by fixing means in order to enable demounting for achange of mold, in particular to proceed to the production of containersof different shapes and/or different sizes or to replace them in theevent of damage to and/or wear of the half-molds.

To reduce production costs as much as the time necessary for suchdemounting of the mold, various improvements to the molding devices arealready proposed in the document EP-B1-0 821 641.

According to the teachings of the above document, means for regulatingthe temperature of the imprints of each half-mold are produced in a part(called the shell-carrier in the above document) separate from thehalf-mold (called a shell in the above document). The shell-carrier isintended to be fixed permanently to the mold-carrier, whereas thehalf-mold provided with the half-imprint is adapted to be removablyfastened to the shell-carrier by fast fixing means. This configurationenables a light half-mold to be produced that is easily manipulated by asingle operator.

The means for fixing the half-mold onto the mold-carrier are disposed onrespective edges of the half-mold and the shell-carrier that areparallel to the main axis of the imprint. These fixing means include inparticular a locking lug mounted on the mold-carrier in a fixed ormobile manner projecting over the joint face of the half-mold to fix thehalf-mold firmly to the shell-carrier. The half-mold is clamped againstthe bottom of the recess by fast screwing of the locking lugs onto ajoint face of the mold-carrier.

With the fixing means known in the art, the mounting and demountingoperations are carried out by at least one operator and require the useof tools, such as screwdrivers, to demount the fixing bar with themold-carriers in the open position.

The document WO-A-2007/012308 proposes to clamp the half-mold againstthe bottom of the recess by means of a set of springs that areinterleaved between a drive element and a base element that carries thelocking lugs. The movement of the control element enables, over a firstpart of its travel, driving of the movement of the locking lugs betweena retracted position and an active position, and then, over a secondpart of its travel, clamping of the locking lugs in the active positionagainst the half-mold by way of the springs.

Such fixing and clamping means nevertheless include numerous movingparts. These fixing means are therefore complex and costly tomanufacture.

Furthermore, the drive means proposed in the above document necessitatethe use and manipulation of a tool by the operator carrying out themounting operation.

The aim is therefore to reduce further the time necessary for mountingand demounting the half-molds in such a manner as to reduce further theintervention time, by means of fast fixing means that are simple and ofrelatively low cost to manufacture.

To this end, the invention proposes a molding device of the typedescribed above characterized in that each fixing bolt and/or theassociated half-mold includes a clamping ramp that is inclined in such amanner as to press the half-mold against the bottom of the recess onsliding of said fixing bolt from its retracted position to its activeposition.

According to other features of the invention:

-   -   each fixing bolt and/or the associated half-mold includes a        clamping ramp that is inclined in such a manner as to press the        half-mold against the bottom of the recess on sliding of said        fixing bolt from its retracted position to its active position;    -   the recess has an entry in a transverse plane that is delimited        transversely by a vertical first edge and a vertical second        edge;    -   each fixing bolt is mounted to slide transversely between its        active position in which said fixing bolt projects through the        entry of the recess and its retracted position in which it is        completely retracted relative to the entry of the recess;    -   the sliding of each fixing bolt is driven by driving means        integrated into the mold-carrier;    -   the drive means include at least one vertical transmission shaft        that is rotatably mounted in the mold-carrier and said drive        means include means for transforming the rotation movement of        the transmission shaft into sliding movement of at least one        fixing bolt;    -   the transmission shaft is connected to at least one fixing bolt        by a cam mechanism that transforms rotation movement of the        transmission shaft into sliding movement of said fixing bolt;    -   the transmission shaft is connected to said fixing bolt by a cam        and frame mechanism;    -   the transmission shaft includes a pinion that cooperates with a        rack of the fixing bolt to drive sliding of the fixing bolt;    -   the transmission shaft is a cranked shaft that is articulated to        the fixing bolt by a link for transforming rotation movement of        the transmission shaft into sliding movement of the fixing bolt;    -   the drive means include at least one handle that is intended to        be actuated manually by an operator to drive sliding of each        fixing bolt between its two positions;    -   each handle is formed by an arm that is orthogonal to the        transmission shaft and is fixed to one end of the associated        transmission shaft;    -   the molding device includes at least two fixing bolts that are        slidably mounted at the border of the first edge of the entry of        the recess;    -   sliding of all the fixing bolts of the first edge is driven by a        common first transmission shaft;    -   the molding device includes at least one lug for locking the        half-mold in the mounted position that is carried in fixed        manner by the mold-carrier at the border of the opposite second        edge of the entry of the recess;    -   the molding device includes at least two other retractable        fixing bolts that are slidably mounted at the border of the        opposite second edge of the entry of the recess;    -   sliding of all the fixing bolts of the second edge is driven by        a common second transmission shaft;    -   at least one fixing bolt is formed by a ball;    -   the molding device includes a safety device that locks the        fixing bolts in their active position.

Other features and advantages will become apparent on reading thefollowing detailed description, to understand which reference should bemade to the appended drawings, in which:

FIG. 1 is a perspective view showing a blowing device produced accordingto the teachings of the invention and including two mold-carriersprovided with their half-mold, the mold-carriers being in the openposition;

FIG. 2 is a perspective view showing the two half-molds from FIG. 1 in aseparated position;

FIG. 3 is a perspective view showing the two half-molds from FIG. 2 in ajoined position;

FIG. 4 is a view similar to that of FIG. 1 showing the two mold-carriersin a closed position;

FIG. 5 is a perspective view showing a mold-carrier including acontrolled fixing device in its retracted position and a half-mold in ademounted position;

FIG. 6 is a front view showing the mold-carrier from FIG. 5 and in whichthe half-mold is mounted and fixed;

FIG. 7 is a view in section taken along the line 7-7 in FIG. 6 showing afixing bolt in its active position;

FIG. 8 is a view similar to that of FIG. 6 showing the half-mold mountedin but not fixed to the mold-carrier, the fixing device being retracted;

FIG. 9 is a view in section taken along the line 9-9 in FIG. 8 showingthe fixing bolt in its retracted position;

FIG. 10 is an exploded perspective view showing a transmission shaft ofthe drive means of the fixing device and a border bar of themold-carrier in which it is to be mounted;

FIG. 11 is an exploded perspective view that shows the shaft mounted inthe border bar, the bolts to be slidably mounted in the border bar andthe screws fixing the border bar to the mold-carrier; and

FIG. 12 is a view in section taken along the line 12-12 in FIG. 1showing a safety device that locks the bolts in the active position.

In the remainder of the description, elements having similar, analogousor identical functions are designated by the same reference numbers.

In the remainder of the description, there are adopted without thisbeing limiting on the invention longitudinal, vertical and transverseorientations for each mold-carrier 32 indicated by the orthogonal frameof reference “L,V,T” for the first mold-carrier 32 on the left in FIG. 1and “L′,V,T” for the second mold-carrier on the right in FIG. 2. Thusthe transverse directions “T” and “T” and the longitudinal directions“L” and “L” are fixed relative to each mold-carrier 34. For eachmold-carrier 32, the longitudinal direction “L”, “L” is oriented fromthe rear toward the front in the direction of the other mold-carrier 32when the mold-carriers 32 are in the closed position.

The terms “interior”, respectively “exterior” are adopted to designate aface or a direction facing toward the interior, respectively exterior ofthe recess 38 of a mold-carrier.

There is shown in FIG. 1 a molding device 10 for a machine (not shown)for production of thermoplastic material containers, in particularbottles, by blowing or drawing-blowing a pre-heated preform.

The molding device 10 shown in FIG. 1 nevertheless constitutes only onenonlimiting embodiment of the type of molding device 10 to which fixingmeans produced according to the teachings of the invention may beapplied.

The molding device 10 shown in FIG. 1 is more particularly intended toequip a station of a “rotary” type production machine, i.e. onegenerally including a carousel at the circumference of which aredisposed stations each comprising a molding device 10 associated withblowing or drawing-blowing means, also known as blowing nozzles.

Nevertheless, the fixing means of the invention may equally well be usedin a production machine of linear (and not rotary) type.

See for example the document FR-A-2-764 544 for more details of blowingor drawing-blowing means.

As may be seen in detail in FIGS. 2 and 3, the molding device 10includes at least one mold 12 constituted of two half-molds 14 that aremirror images or each other with respect to their joint plane. Here themold 12 has a cylindrical shape divided axially into two parts to formeach half-mold 14.

As shown in FIG. 2, each half-mold 14 includes a half-imprint 16 of thefinal container recessed into a front joint face 18. Here the joint face18 is a plane vertical transverse face that is formed by the sectionface of the cylinder forming the mold 12.

The half-molds 14 are adapted to occupy a separated position, as shownin FIG. 2, in which the two half-molds 14 are spaced from each other,and a joined position, as shown in FIG. 3, in which the two half-molds14 are joined together at their joint face 18 to form the mold 12.

Each half-mold 14 further includes a rear face 20 opposite the jointface 18 and having the overall shape of a circular half-cylindersubstantially coaxial with the vertical main axis “X” of the imprint 16of the container.

Each half-mold 14 has two vertically oriented rectilinear edges 22 atthe junction between its joint face 18 and its rear face 20.

In the joined position, the mold 12 has a circular horizontal upper face24 with a central opening 26 adapted to enable entry of the blowing air,or even of a drawing rod.

The upper face 24 of each half-mold 14 is preferably formed by twoseparate plates 28 each of which is firmly attached to a half-mold 14.The lower end of a nozzle (not shown) comprising the blowing ordrawing-blowing means is adapted to come into contact with the upperface 24 formed by the two plates 28.

The half-molds 14 further include in their upper part, just below thehorizontal upper face, an annular groove 30 that extendscircumferentially and continuously around the two half-molds 14 whenthey are joined.

If the container to be produced has a bottom of complex shape, inparticular a petal shape, problems are likely to arise with removal fromthe mold.

It is for this reason that there is then advantageously provided aseparate mold bottom (not shown), separate from the half-molds 14, saidmold bottom including an imprint of the bottom of the containercomplementary to the half-imprints 16.

Each half-mold 14 is intended to be demountably fixed to an associatedmold-carrier 32 of the molding device 10. Such mold-carriers 32 areshown in more detail in FIGS. 1 and 4.

The two mold-carriers 32 are mounted to be mobile relative to each otherbetween a closed position, as shown in FIG. 4, in which the twohalf-molds 14 are joined to form the imprint 16, and an open position,as shown in FIG. 1, in which the two half-molds 14 are separated, forexample to enable extraction of a container after blowing.

In the example shown in FIGS. 1 and 4, the mold-carriers 32 areconstituted in the form of two carrier structures articulated about acommon hinge 34 with a vertical pivot axis “O”. The hinge 34 isgenerally carried by a bracket (not shown) that is fixed relative to thecarousel.

The mold-carriers 32 are then able to move apart from each other bypivoting about the axis “O” and are consequently mounted to pivotbetween their open position (FIG. 1) and their closed position (FIG. 4).

As shown in FIG. 1, when the mold-carriers 32 are opened from theirclosed position, they begin to move away from each other in a rearwardlyoriented longitudinal opening direction that is orthogonal to the jointface 18 of the half-molds 14.

Because of the kinematics of the mold-carriers 32, such a molding device10 is referred to as a “book-like opening” mold.

In a variant of the invention that is not shown, the molding deviceincludes two mold-carriers mounted to be mobile in translation relativeto each other in a longitudinal direction between an open position and aclosed position.

The molding device 10 further includes a lock 36 that is transverselydisposed diametrically opposite the hinge 34 relative to the verticalaxis “X” of the imprint 16, as shown in FIG. 4.

This kind of lock 36 is also known in the art and is therefore notdescribed in more detail here. This lock 36 has the notable function ofpreventing any inopportune opening during blowing, where the pressuresmay reach 40 bars, depending on the application.

For fuller details on the structure and operation of such a lock 36, seefor example the document FR-A-2 646 802, which includes a generaldescription of a similar lock.

The mold-carriers 32 and the half-molds 14 being substantially mirrorimages of each other with respect to the joint plane of the mold-carrier32, there is described hereinafter only the mold 12 situated on the leftin FIG. 1, the description being applicable to the other by reason oftheir symmetry.

As shown in FIG. 5, the half-mold 14 is more particularly adapted to bereceived in a recess 38 of the associated mold-carrier 32 to occupy amounted position.

The molding device 10 includes fixing means that are adapted to fix eachhalf-mold 14 demountably in the mounted position in the recess 38 of theassociated mold-carrier 32. These means are described in more detailhereinafter.

The recess 38 is delimited longitudinally toward the rear by a concavebottom 40 of semi-cylindrical shape complementary to the rear face 20 ofthe half-mold 14.

Moreover, the recess 38 is delimited in the vertically upward directionby the lower face of a rim 42 that extends radially inward, projectingrelative to the bottom 40 of the recess 38. The groove 30 in thehalf-mold 14 is adapted to be nested longitudinally with this rim 42 toenable vertical positioning and retention of the half-mold 14 relativeto the mold-carrier 32.

The entry of the recess 38 is furthermore delimited transversely on theone hand by a first vertical edge 44 and on the other hand by a secondvertical edge 46. The edge 46 situated in the vicinity of the hinge 34is referred to as the proximal edge and the edge 44 farther away fromthe hinge 34 is referred to as the distal edge.

Each of the distal and proximal edges 44, 46, respectively, of therecess 38 is bordered by a distal vertical border bar 45, a proximalvertical border bar 47, respectively, that is fixedly attached to thestructure of the mold-carrier 32 by rigid fixing means such as screws48. Each border bar 45, 47 has a rectangular or square contourhorizontal section.

Each border bar 45, 47 is in particular delimited longitudinally by avertical transverse front mating face 50, visible in FIG. 5, and by avertical transverse rear contact face 51, visible in FIG. 10, by whichit is fixed to the mold-carrier 32. Each border bar 45, 47 is alsodelimited transversely by two lateral faces 53 respectively interior andexterior relative to the recess 38.

The mating face 50 of each border bar 45, 47 is intended to come intoplane contact with the mating face 50 of a facing border bar 45, 47 ofthe other mold-carrier 32 when the mold-carriers 32 in their closedposition. In the mounted position of the half-mold 14, its joint face 18is substantially coplanar with the mating faces 50 of the border bars45, 47 that border the recess 38, as is particularly visible in FIG. 1.

Moreover, the mold-carrier 32 is provided with means (not shown) forregulating the temperature of the imprint 16 that are formed by conduitsformed in the thickness of the bottom 40 of the recess 38 and in which aheat-exchange fluid circulates.

After fixing the half-mold 14 in its mounted position in themold-carrier 32, the rear face 20 of the half-mold 14 and the bottom 40of the recess 38 of the mold-carrier 32 are in clamped contact, pressedagainst each other. Accordingly, the transmission of heat between thehalf-mold 14 and the mold-carrier 32 is obtained by conduction betweenthe rear face 20 of the half-mold 14 and the bottom 40 of the recess 38.

The molding device 10 includes fixing means adapted to fix eachhalf-mold 14 occupying a mounted position in a demountable manner to themold-carrier 32. These fixing means are also adapted to clamp thehalf-mold 14 against the bottom 40 of the associated recess 38 of themold-carrier 32 to press the rear face 20 of the half-mold 14 againstthe bottom 40 of the recess 38. Thus there remains no air film liable toinsulate the half-mold 14 thermally from the mold-carrier 32.

The fixing means for only one module-carrier 32 are describedhereinafter, the fixing means for the other mold-carrier 32 beingidentical.

The fixing means are at least in part controllable. In the example shownin FIGS. 6 and 8, the controllable fixing means are disposed only at theborder of the distal edge 44 of the recess 38, the other, proximal edge46 being equipped with passive fixing means.

In the example shown in FIGS. 6 and 8, the passive fixing means includeat least one lug 52 for locking the half-mold 14 in the mounted positionthat is carried in fixed manner by the mold-carrier 32 at the border ofthe proximal edge 46.

Here there are three locking lugs 52 distributed along the proximal edge46 of the recess 38. They project transversely inward relative to theproximal edge 46 of the bottom 40 of the recess 38.

Moreover, as seen clearly in FIG. 1, the locking lugs 52 are flush withor longitudinally set back rearwardly relative to the joint face 18 ofthe half-mold 14 in the mounted position in order to prevent anyinterference on closing the mold 12.

Each locking lug 52 is intended to be received in a rebate 54 producedin the corresponding edge 22 of the half-mold 14. The locking lugs 52are more particularly intended to be pressed longitudinally against atransverse vertical front fixing face 56 of the half-mold 14 in thebottom of the rebate 54.

In known manner, the locking lugs 52 are all carried by the commonproximal border bar 47, sometimes referred to as the “black bar”. Theproximal border bar 47 is permanently fixed to the mold-carrier 32, forexample by means of screws 48. These locking lugs 52 are thus intendedto remain in place during operations of changing the half-mold 14.

The controllable fixing means include at least one fixing bolt 58 thatis mounted in the mold-carrier 32 to be mobile between:

-   -   an active position, as shown in FIGS. 6 and 7, in which it is        extended to fix in demountable manner the half-mold 14 in its        mounted position and clamped against the bottom 40 of the        associated recess 38 by at least one locking face 60 of each        fixing bolt 58 bearing against an associated fixing face 56 of        the half-mold 14; and    -   a retracted position in which the fixing bolt 58 frees the entry        of the recess 38 to enable the half-mold 14 to pass.

As for the locking lugs 52, in its active position, each fixing bolt 58is set back longitudinally toward the rear relative to, or at leastflush with, the joint face 18 of the half-mold 14.

Moreover, each fixing bolt 58 is advantageously mounted to be mobile insuch a manner as not to project longitudinally toward the front beyondthe joint face 18 of the half-mold 14 at any point on its trajectorybetween its two positions. This enables driven movement of the fixingbolt 58 even when the mold-carriers 32 are in their closed position.

A free interior transverse end section 62 of each fixing bolt 58 isintended to be received in an associated rebate 54 produced in thecorresponding edge 22 of the half-mold 14 when the half-mold 14 is inits mounted position. The vertical transverse bottom of each rebate 54forms a fixing face 56 of the half-mold 14.

Alternatively, the rebate is replaced by a mortise produced in thehalf-mold.

The mold-carrier 32 includes at least two fixing bolts 58 at the borderof the distal edge 44 of the entry of the recess 38. Here there arethree fixing bolts 58 distributed along the distal edge 44 of the entryof the recess 38.

All the fixing bolts 58 look identical in the embodiment shown in thefigures. Therefore only one fixing bolt 58 is described hereinafter.

Referring to FIGS. 7 and 9, the fixing bolt 58 has a globallyparallelepipedal shape here. It is delimited longitudinally by a planerear vertical face forming the locking face 60 and by a plane frontvertical face 64.

As shown in FIGS. 7, 9 and 10, each fixing bolt 58 is more particularlymounted to slide transversely in an associated bolt passage 66 producedin the first distal border bar 45 that opens transversely at least inthe direction of the interior of the recess 38.

In the embodiment shown in FIG. 10, each bolt passage 66 is delimitedvertically by two horizontal guide faces 68 and longitudinally towardthe front by a front guide face 70. To facilitate mounting the fixingbolts 58, as explained hereinafter, the bolt passage 66 opens into therear contact face 51 of the distal border bar 45.

Accordingly, as shown in FIGS. 7 and 9, the fixing bolt 58 is alsoguided as it slides transversely by a vertical rear face 72 of themold-carrier 32 in the vertical transverse plane of the entry of therecess 38. Thus each fixing bolt 58 slides on the border of the distaledge 44 of the entry of the recess 38.

In its active position (FIG. 7), the fixing bolt 58 projectstransversely relative to the associated distal edge 44 of the entry ofthe recess 38. In its retracted position (FIG. 9) the fixing bolt 58 istotally retracted relative to said distal edge 44 of the entry of therecess 38.

When the half-mold 14 has been mounted in but not yet fixed to therecess 38, each fixing face 56 of the half-mold 14 on the distal side isslightly longitudinally forward of the locking face 60 of the fixingbolt 58.

As may be seen particularly in FIGS. 7 and 9, each fixing bolt 58includes a clamping ramp 74 that is inclined in such a manner as topress the associated fixing face 56 in the direction of the bottom 40 ofthe recess 38 when said fixing bolt 58 slides from its retractedposition to its active position. Accordingly, each distal side fixingface 56 of the half-mold 14 is then slightly set back longitudinallytoward the rear in such a manner as to be pressed against the lockingface 60 of the fixing bolt 58.

The clamping ramp 74 is formed by a bevel formed in the interiortransverse vertical edge at the edge of the locking face 60. Here theclamping ramp 74 has a rounded appearance.

Alternatively, the clamping ramp is carried by the half-mold.

In another variant of the invention, not shown, the bolt and thehalf-mold are both equipped with an associated clamping ramp. The tworamps then cooperate by sliding on each other to clamp the half-mold tothe bottom of the recess.

Moreover, the sliding of each fixing bolt 58 is driven by drive meansthat are integrated into the mold-carrier 32.

As shown in FIG. 10, the drive means include a vertical transmissionshaft 76 that is rotatably mounted in the mold-carrier 32. Here thetransmission shaft 76 is received in a vertical hole 78 produced in theupper end of the distal border bar 45. The vertical hole thus forms abearing 78 to enable the transmission shaft 76 to turn about a verticalrotation axis “Y”.

Sliding of all the fixing bolts 58 of the distal edge 44 is driven bythe common transmission shaft 76. To this end, the bearing 78 crossesthe three bolt passages 66 and opens onto the horizontal guide faces 68on either side of the front guide face 70.

The transmission shaft 76 is connected to each fixing bolt 58 by a cammechanism that transforms rotation movement of the transmission shaft 76into sliding movement of the fixing bolts 58. To be more precise, thetransmission shaft 76 is here connected to each fixing bolt 58 by aso-called “cam and frame” mechanism.

Thus the transmission shaft 76 includes three cams 80 that are formed bythree circular cylindrical sections with a vertical axis that arearranged eccentrically relative to the rotation axis “Y” of thetransmission shaft 76. These cams 80 are therefore referred tohereinafter as “eccentric sections 80”.

The eccentric sections 80 are arranged to coincide with the boltpassages 66 when the transmission shaft 76 is mounted by inserting itinto its bearing 78, as shown in FIG. 11.

As shown in FIGS. 7 and 9, each eccentric section 80 here has a diameterthat coincides in size and in position with a radius of the transmissionshaft 76.

Each fixing bolt 58 has in its front face 64 a vertical groove 82opening vertically at each end that is intended to receive acorresponding eccentric section 80 of the transmission shaft 76. This isshown in more detail in FIGS. 7 and 9, for example.

The groove 82 more specifically has a transverse width substantiallyequal to the diameter of the eccentric section 80 and a longitudinaldepth that allows longitudinal sliding of the eccentric section 80 inthe groove 82 during rotation of the transmission shaft 76 through atleast one half-turn.

The transmission shaft 76 is thus connected to each fixing bolt 58 by acam and frame mechanism that transforms rotation movement of thetransmission shaft 76 into transverse sliding movement of the fixingbolts 58. Rotation of the transmission shaft 76 also drives retractionand deployment of the fixing bolt 58 between its two positions.

In a variant of the invention that is not shown, the means fortransforming rotation movement of the shaft into sliding movement of thefixing bolt are formed by a pinion carried by the shaft that cooperateswith a rack constrained to slide with the fixing bolt to drive thesliding of the fixing bolt.

In another variant of the invention that is not shown, the transmissionshaft is a cranked shaft that is articulated to the fixing bolt via alink to transform rotation movement of the shaft into sliding movementof the fixing bolt.

According to a further variant of the invention that is not shown, theshaft carries a cam that actively drives sliding movement of the bolttowards one position, the bolt being spring-loaded toward its otherposition.

Moreover, the drive means are intended here to be operated manually byan operator without using an individual tool. To this end, as shown inFIGS. 6 and 8, for example, the drive means include at least one handle84 that is intended to be operated manually by an operator to drivesliding of each fixing bolt 58 between its two positions.

Here the handle 84 is formed by an arm that extends orthogonally to thetransmission shaft 76 and is fixed to the upper end of the transmissionshaft 76 so that it is constrained to rotate about the vertical rotationaxis “Y” with the transmission shaft 76. To this end, the upper end ofthe transmission shaft 76 projects from the vertical hole 78 in thedistal border bar 45.

The arm forming the handle 84 is above an upper face of the mold-carrier32.

The arm forming the handle 84 is sufficiently long to enable theoperator to apply by hand a torque necessary for clamping the half-mold14 to the bottom 40 of the recess 38. The torque is also sufficient toovercome the friction of the locking face 60 of each fixing bolt 58against the associated fixing face 56 of the half-mold 14 when thefixing bolts 58 are retracted to demount the half-mold 14.

Furthermore, as shown in FIG. 12, an indexing finger 86 extendsvertically downward under the arm forming the handle 84. The indexingfinger 86 is adapted to abut against a vertical shoulder face 88 of themold-carrier 32 when the fixing bolts 58 are in their active position.The operator who operates the locking device is thus informed by thecontact of the indexing finger 86 with the shoulder face 88 that thefixing bolts 58 are in their active position.

Thus in the active position of the bolts the arm forming the handle 84is pushed above the mold-carrier 32 in such a manner as to be accessibleeven when the mold-carriers 32 are in their closed position. As shown inFIG. 6, in this position the arm forming the handle 84 does not projectradially outwards relative to the exterior contour of the mold-carrier32.

Alternatively, and referring to FIG. 4, the end of the arm that is fixedto the transmission shaft is conformed in such a manner that that theshaft may be turned toward the retracted position of the fixing boltseven in the closed position of the mold-carrier. Said end of the arm isof semicircular shape, for example, which enables the transmission shaftto turn without interfering with the arm of the other mold-carrier.

To prevent the drive means being triggered inopportunely when thehalf-mold 14 is fixed to the mold-carrier 32, it includes a safetydevice for locking the fixing bolts 58 in their active position.

Here the locking device is formed by a vertical axis peg 90 that ismounted on the arm forming the handle 84 of the transmission shaft 76.The peg 90 is more particularly mounted to slide vertically in theindexing finger 86 between a low position in which it may be insertedinto a complementary locking orifice 92 of the mold-carrier 32 when thefixing bolts 58 are in their active position and a high position inwhich the peg 90 is completely extracted from the locking orifice 92.

Moreover, the upper end of the peg 90 is connected to a button 94 thatenables the operator to pull the peg 90 toward its high position toenable the transmission shaft 76 to be turned in such a manner as todrive the fixing bolts 58 toward their retracted position.

The peg 90 is advantageously spring-loaded into its low position inorder to automate the safety device, for example by a spring (not shown)that is placed around the peg 90, in a cylindrical internal chamber ofthe finger 86. The spring bears on the one hand on a lower internal wallof the finger and on the other hand on a lower wall of the button 94.

The mold-carrier 32 further includes an inclined plane 96 that isdisposed on the trajectory of the peg 90 on rotation of the transmissionshaft 76 toward the active position of the fixing bolts 58. Thisinclined plane 96 enables the peg 90 to be driven automatically towardits high position on rotation of the transmission shaft 76 toward theactive position of the fixing bolts 58. Accordingly, the lower free endof the peg 90 is able to slide automatically along the inclined plane 96and then a horizontal plane as far as the locking orifice 92 in which itis spring-loaded into its low position.

As shown in FIG. 10, on mounting the controllable fixing means on themold-carrier 32, the distal border bar 45 is demounted from themold-carrier 32. The transmission shaft 76 is first inserted verticallyinto the bearing 78 of the distal border bar 45 until the arm formingthe handle 84 comes into abutment.

The fixing bolts 58 are then inserted longitudinally into the boltpassages 66 opening onto the rear contact face 51, before the distalborder bar 45 is fixed to the mold-carrier 32 by the fixing screws 48.This operation is shown in FIG. 11. The fixing bolts 58 are thereforetrapped in their bolt passage 66 by interengagement with the eccentricsections 80.

The shanks of said screws 48 also cooperate with annular grooves 98 ofthe transmission shaft 76, visible in FIG. 10, to retain thetransmission shaft 76 vertically in position in the distal border bar45.

During an operation to change the mold 12, the operator proceeds firstto demount a first mold 12.

The operator first moves the mold-carriers 32 equipped with a first mold12 apart into their open position.

The operator then grasps the arm forming the handle 84 of thecontrollable fixing device by pulling on the peg 90 so as to be able toturn the transmission shaft 76 in a first anticlockwise unlockingdirection.

The fixing bolt 58 being in its active position, as shown in FIG. 7, theanticlockwise rotation of the transmission shaft 76 presses theeccentric section 80 against the external wall of the groove 82, therebycausing the fixing bolt 58 to slide transversely toward its retractedposition.

During sliding of the fixing bolt 58, because of the depth of the groove82 the eccentric section 80 slides longitudinally relative to the fixingbolt 58 without acting longitudinally on the fixing bolt 58.

The transmission shaft 76 and its arm forming the handle 84 are then inthe position shown in FIG. 8. The fixing bolts 58 are therefore in theirretracted position.

The half-mold 14 of the first mold 12 to be changed being released andloosened, the operator grasps the half-mold 14 to remove it by a firstpivoting movement about its vertical axis “X” to disengage the half-mold14 from the fixed locking lugs 52 and then movement in longitudinaltranslation in the forward direction of the half-mold 14 that has beenpivoted in this manner.

The half-mold 14 of the replacement second mold 12 is then mounted onthe mold-carrier 32 by the reverse movements of translation and thenpivoting.

As each fixing bolt 58 slides from its retracted position toward itsactive position, the transmission shaft 76 is turned clockwise in such amanner that the eccentric section 80 bears on the interior wall of thegroove 82 to cause each fixing bolt 58 to slide.

The clamping ramp 74 enables the rear face 20 of the half-mold 14 to beclamped against the bottom 40 of the recess 38, after which the blockingface 60 enables clamping.

During this operation, the peg 90 is automatically driven into its highposition by the inclined plane 96. The peg 90 is then returned by springmeans into its low position in the locking orifice 92 when the indexingfinger 86 abuts against the shoulder face 88 of the mold-carrier 32. Thefixing bolts 58 are then in their active position.

Thus the operator is able to mount and demount a half-mold 14 simply andquickly, without using additional tools.

In a variant of the invention that is not shown the rotation of theshaft is driven automatically by motorized means.

In another variant of the invention that is not shown, the locking lugsof the proximal edge of the entry of the recess are replaced by lockingmeans with retractable bolts similar to the means just described for thedistal edge. Sliding of all the fixing bolts of the proximal edge isadvantageously driven by a common second transmission shaft.

In this latter variant, the recess of the mold-carrier is advantageouslydesigned so that the half-mold is mounted in and demounted from itsrecess by a single movement in translation parallel to the opening ofthe mold formed by the two half-molds, here by a longitudinal movement.Thus the two edges of the recess are released simultaneously by thefixing bolts. It is then no longer necessary to pivot the half-mold 14when mounting and demounting it.

In a further variant of the invention that is not shown, each bolt isformed by a trapped ball mobile in the bolt passage 66. Thus only a domeportion of the ball projects from the bolt passage when the bolt is inits active position.

The invention claimed is:
 1. Molding device for a machine for producingthermoplastic material containers, by blowing or drawing-blowing apreform, the molding device including: two half-molds each of which isprovided with a half-imprint and each of which includes a front jointface and a rear face; two mold-carriers each of which is provided with arecess intended to receive an associated one of said half-molds in amounted position in which the rear face of the half mold is in contactwith a bottom of the recess; and at least one retractable fixing boltthat is slidably mounted in at least one of said mold-carriers to slidebetween an active position in which said fixing bolt is extended to fixin demountable manner the associated half-mold in the mounted positionclamped against the bottom of the associated recess by at least onelocking face of each fixing bolt bearing against an associated fixingface of the half-mold, and a retracted position in which said fixingbolt releases the half-mold, each fixing bolt includes a clamping rampthat is inclined in such a manner as to press the half-mold against thebottom of the recess on sliding of said fixing bolt from said retractedposition to said active position, characterized in that the recess hasan entry in a transverse plane that is delimited transversely by avertical first edge and a vertical second edge, and in that each fixingbolt is mounted to slide transversely between said active position inwhich said fixing bolt projects through the entry of the recess and saidretracted position in which said fixing bolt is completely retractedrelative to the entry of the recess.
 2. Device according to claim 1,characterized in that the sliding of each fixing bolt is driven by drivemeans integrated into the mold-carrier.
 3. Device according to claim 2,characterized in that the drive means include: at least one verticaltransmission shaft that is rotatably mounted in the mold-carrier; andmeans for transforming rotation movement of the transmission shaft intosliding movement of at least one of said at least one fixing bolts. 4.Device according to claim 3, characterized in that the transmissionshaft is connected to at least one of said at least one fixing bolts bya cam mechanism that transforms rotation movement of the transmissionshaft into sliding movement of said fixing bolt.
 5. Device according toclaim 4, characterized in that the transmission shaft is connected tosaid fixing bolt by a cam and frame mechanism.
 6. Device according toclaim 3, characterized in that the transmission shaft includes a pinionthat cooperates with a rack of the fixing bolt to drive sliding of thefixing bolt.
 7. Device according to claim 3, characterized in that thetransmission shaft is a cranked shaft that is articulated to the fixingbolt by a link for transforming rotation movement of the transmissionshaft into sliding movement of the fixing bolt.
 8. Device according toclaim 3, characterized in that the drive means include at least onehandle that is intended to be actuated manually by an operator to drivesliding of each fixing bolt between said two positions.
 9. Deviceaccording to claim 8, characterized in that each handle is formed by anarm that is orthogonal to the transmission shaft and is fixed to one endof the associated transmission shaft.
 10. Device according to claim 3,comprising at least two fixing bolts that are slidably mounted at aborder of the first edge of the entry of the recess.
 11. Deviceaccording to claim 10, characterized in that sliding of all the fixingbolts of the first edge is driven by a common first transmission shaft.12. Device according to claim 11, comprising at least one lug forlocking the half mold in the mounted position that is carried in fixedmanner by the mold-carrier at a border of the opposite second edge ofthe entry of the recess.
 13. Device according to claim 11, comprising atleast two other retractable fixing bolts that are slidably mounted atthe border of the opposite second edge of the entry of the recess. 14.Device according to claim 13, characterized in that sliding of all thefixing bolts of the second edge is driven by a common secondtransmission shaft.
 15. Device according to claim 1, characterized inthat at least one of said at least one fixing bolts is formed by a ball.16. Device according to claim 1, comprising a safety device that locksthe fixing bolts in their active position.
 17. Device according to claim2, characterized in that the drive means include at least one handlethat is intended to be actuated manually by an operator to drive slidingof each fixing bolt between said two positions.
 18. Device according toclaim 4, characterized in that the drive means include at least onehandle that is intended to be actuated manually by an operator to drivesliding of each fixing bolt between said two positions.
 19. Deviceaccording to claim 5, characterized in that the drive means include atleast one handle that is intended to be actuated manually by an operatorto drive sliding of each fixing bolt between said two positions. 20.Device according to claim 6, characterized in that the drive meansinclude at least one handle that is intended to be actuated manually byan operator to drive sliding of each fixing bolt between said twopositions.